Tradescantia tucumanensis M.Pell., 2018

Pellegrini, Marco O. O., 2018, Wandering throughout South America: Taxonomic revision of Tradescantia subg. Austrotradescantia (D. R. Hunt) M. Pell. (Commelinaceae), PhytoKeys 101, pp. 1-97 : 44-50

12. Tradescantia tucumanensis M.Pell. sp. nov. Figs 30 , 31

Diagnosis.

Similar to T. tenella due to its definite base, densely branched stems, hirsute leaves, conspicuous secondary veins, saccate and strongly unequal cincinni bracts, keeled sepals, flat petals, pistil the same length as the stamens, seeds with rugose testa and hilum shorter than ½ the length of the seed. It can be differentiated by its prostrate stems with ascending apex, sessile to subpetiolate leaves, hyaline to light brown hairs, ellipsoid floral buds and sepals with a mixture of glandular and eglandular hairs, but exclusively hispid along the keel.

Type.

BOLIVIA. Santa Cruz: Florida, Tierras Nuevas, km 55 camino de Mairana a Postrevalle , fl., fr., 21 Nov 2004, J.R.I. Wood & H. Huayalla 21010 (holotype: K!; isotype: HSB!) .

Description.

Herbs ca. 20-55 cm tall, with a definite base, terrestrial or rupicolous, rarely epiphytes. Stems erect, sometimes prostrate with ascending apex, succulent, little to densely branched; internodes 1.6-12.1 cm long at base, distally shorter, medium to dark green or vinaceous, sometimes with green longitudinal striations or spots, velutine to hispid, sometimes becoming glabrous with age, with a leaf-opposed longitudinal line of short, uniseriate, hyaline hairs in the terminal portion of the stems. Leaves distichously-alternate, sessile to subpetiolate; ptyxis involute; sheaths 0.4-1 cm long, medium green, with longitudinal vinaceous striations, sparsely velutine to hispid, margin setose, hairs hyaline to light brown; petiole 0.2-1.2 cm long to indistinct in the apical leaves; blades 1.1-8.7 × 0.9-3.2 cm, narrowly lanceolate to lanceolate or ovate to broadly ovate, flat, membranous to chartaceous, sparsely hispid to hispid on both sides, hairs hyaline to light brown, adaxially medium to dark green, abaxially light to medium green or vinaceous, turning medium brown to olive-green when dry, base cordate to round, margin green, ciliate, slightly revolute, apex acute to acuminate; midvein conspicuous, adaxially impressed, secondary veins conspicuous, adaxially impressed, abaxially inconspicuous, becoming evident when dry. Synflorescences terminal or axillar in the distal portion of the stems, composed of a solitary main florescence, 1 per leaf axis. Inflorescences (main florescences) consisting of a pedunculate double-cincinni fused back to back; peduncles (0.8-2.0-)3.4-8.2 cm long, velutine to hispid, with a leaf-opposed longitudinal line of short, uniseriate hairs, in the terminal portion of the stems, hairs hyaline to light brown; cincinni bracts 1.1-4.8 × (0.5-)1-2.7 cm, leaf-like, unequal to strongly unequal to each other, rarely similar to each other, elliptic or ovate to broadly ovate, sparsely hispid, hairs hyaline to light brown, adaxially medium to dark green, abaxially light to medium green or vinaceous, base cordate to obtuse, saccate, margins ciliolate to hispid, hairs hyaline to light brown, slightly revolute, apex acute to acuminate; double cincinni (4-)6-12-flowered. Flowers 1.2-1.6 cm diam., pedicels 0.7-2.2 cm long, vinaceous, with a mixture of glandular and eglandular hairs; floral buds ellipsoid; sepals 3.1-7.6 × 2.4-3.5 mm, keeled, green, with a mixture of glandular and eglandular hairs, hispid along the keel composed exclusively by eglandular hairs, hyaline to light brown; petals 6.6-7.2 × 3.3-5.2 mm, white to pink; filaments 5.6-6.3 mm long, anthers 0.6-0.7 × 0.8-0.9 mm; ovary 0.7-0.9 × 0.7-0.9 mm, style 5.4-6.5 mm long; pistil the same length as the stamens. Capsules 3.2-4.1 × 2.3-3.8 mm. Seeds 1.4-2.4 × 1-1.4 mm, testa grey, not cleft towards the embryotega, rugose; hilum shorter than or equal to ½ the length of the seed.

Specimens seen.

(paratypes). ARGENTINA. Capital: Villa Lujau, fl., 15 Nov 1922, S. Venturi 1981 (CORD, SI, US). Catamarca: Andalgalá, Esquena Grande, fl., 10 Nov 1916, P. Jörgensen 1817 (CORD, SI, US). Chaco: Colonia Benitez, fl., Dec 1935, A.G. Schulz 365 (CORD, SI); Laguna Blanca, fl., fr., 7 Dec 1939, M. Birabén 53 (LP). Córdoba: Villa General Belgrano, fl., 6 Sep 1985, M.E. Múlgura et al. 417 (CORD, MBM). Corrientes: Concepción, Carambola, fl., fr., 25 Sep 1971, T.M. Pedersen 9845 (L, SI); General Paz, G. Lomas de Vallejos, fl., 29 Aug 1973, A. Schinini & C. Quarín 6977 (CORD, CTES, SI); Ituzaingó, Ea. San Pedro, 27°45'S, 56°52'W, fl., fr., 12 Nov 1976, M.M. Arbo et al. 1172 (CORD, CTES); Mburucuyá, Estancia San Juan, fl., 22 Sep 1952, T.M. Pedersen 1835 (L); Mercedes, Ruta Nacional 14, laguna Iberá, 28°32'S, 57°10'W, fl., fr., 5 Nov 1973, M.N. Correa et al. 5306 (CORD, SI); Reserva Nat. Prov. Ibera, Paso Picada, costa W de la laguna Ibera, fl., fr., 11 Dec 1992, S.G. Tressens et al. 4342 (CTES, MBM, U); San Luis del Palmar, 10 km SE de San Luis del Palmar, Ruta 6, fl., 26 Sep 1973, C. Quarín & S.G. Tressens 1399 (CORD, CTES, SI); fl., 24 Oct 1976, A. Schinini & C.L. Cristóbal 13683 (SI). Formosa: Guaycolec, Monte, fl., Aug 1919, P. Jörgensen 3020 (BA, SI, US); Quebrada de Lules, fl., 21 Nov 1910, S. Venturi 1074 (BA, CORD, LP, SI, US). Jujuy: 13km del desvío de la Ruta Nacional 9, caminho a Tiraxi, fl., fr., 10 Aug 1998, O. Morrone et al. 3228 (CORD, SI); caminho a Tiraxi, 24°00'25"S, 65°22'19"W, fl., fr., 14 Nov 2005, F.O. Zuloaga et al. 8703 (CORD, SI); Ledesma, Abra de Cañas, caminho a Valle Grande, fl., fr., 31 Oct 1974, A.L. Cabrera et al. 25612 (LP); fl., fr., 7 Nov 1973, A.L. Cabrera et al. 23938 (CORD, LP, SI); fl., fr., 7 Nov 1973, A.L. Cabrera et al. 23945 (CORD, LP, SI); La Candelaria, El Trementinal, fl., Nov 1974, O. Marvin 19 (LP); caminho a Valle Grande, 24km NW de Libertador General San Martín, fl., 8 Nov 1974, A. Krapovickas et al. 26591 (CORD, CTES, SI); entre Mesada de las Colmenas y Abra Cañas, fl., 21 Oct 1979, A.L. Cabrera et al. 30908 (CORD, SI); caminho a Valle Grande desde Ruta Nacional 34, km 30, fl., fr., 16 Dec 1986, F.O. Zuloaga 2931 (CORD, SI); San Salvador de Jujuy, Zapla, fl., 9 Nov 1974, A.E. Burkart et al. 30419 (CORD, LP, SI); Sierra de Zapla, fl., 15 Nov 1980, A.L. Cabrera et al. 32027 (CORD, SI); fl., fr., 14 Nov 1992, R. Kiesling et al. 8263 (CORD, SI); Parque Nacional Calilegua, fl., 22 Nov 1986, O. Ahumada 5360 (CTES); fl., fr., 30 Sep 1994, O. Ahumada 7167 (CORD, CTES); monolito, 23°40'S, 64°54'W, fl., 3 Nov 1998, O. Ahumada & J. Agüero 8581 (CORD, SI); hasta el Arroyo Tres Cruces, por Ruta Provincial 83, 23°38'S, 64°56'W, fl., fr., 6 Nov 1998, O. Ahumada et al. 8764 (CORD, SI); Ruta Provincial 83, de a Abra de Cañas a Mesada de las Colmenas, 23°41'S, 64°54'W, fl., fr., 11 Nov 2002, F.O. Zuloaga et al. 7500 (CORD, SI); Santa Barbara, subida al Centinela, fl., fr., 12 Dec 1983, A. Rotman 939 (CORD, CTES, SI); Valle Grande, ruta 83, a 2km de San Francisco, fl., fr., 18 Jan 2002, G. Seijo et al 2755 (CORD, CESJ, CTES). Salta: Anta, Parque Nacional El Rey, fl., fr., 10 Nov 1974, T.M. Pedersen 10812 (CORD, L, SI); fl., fr., 14 Jan 1981, A. Brown et al. 1076 (CORD, SI); fl., Oct 2005, S. Chaluklan s.n. (SI barcode SI078836); Orán, Finca San Andrés, 23°05'53"S, 64°37'65"W, Sierra de Zenta, fl., 2 Nov 1997, A. Schinini et al. 33138 (CORD, CTES, SI); Salta, fl., 25 Oct 1985, C.A. Palací 221 (CORD); Santa Victoria, Ruta Provincial 19, 16km de Los Toldos, camino a Lipeo, fl., fr., 19 Nov 2001, O. Morrone et al. 3806 (CORD, SI). Tucumán: Chichigasta, Estancia Las Pavas, fl., fr., 9 Jul 1925, S. Venturi 4060 (CORD, SI, US); fl., 20 Nov 1926, S. Venturi 4705 (BA, CORD, SI, US); Entre Río Cochuna y Río Dulce, camino a Alpachiri, km 28.5, fl., 15 Oct 1966, N.M. Bacigalupo s.n. (CORD no. 467185, SI no. 26088). Famaillá, entre Famaillá y Santa Lucía, fl., fr., 4 Nov 2002, A.A. Cocucci 1982 (CORD). Ghieligasta, Puente del Rio Boehima, fl., 24 Nov 1938, D.C. O’Donell 10733 (US). Jafí, Jeoba Reserva, fl., 14 Nov 1923, S. Venturi 2386 (CORD, SI). Monteros, Rio de las Sosa, fl., 18 Oct 1948, L.B. Smith 4633 (US); km 33 La Helodera, fl., 10 Feb 1972, K. Jones et al. 10448 (CORD, SI). Rio Cochuna, fl., 24 Nov 1938, R. Schreiter 94754 (US); entre río Cochuna y río Dulce, camino a Alpachiri, fl., fr., 15 Oct 1966, N.M. Bacigalupo 26088 (SI). BOLIVIA. Chuquisaca: between Padilla and Monteagudo, between Leque Pampa and El Rosal, fl., 1 Jan 1995, J.R.I. Wood 9080 (K). Santa Cruz: M.M. Caballero, Comarapa, ca. 0.5-1 km pasando el Abra del Cerro Bravo, fl., fr., 20 Nov 2005, J.R.I. Wood & M. Mendoza 2209 (HSB, K). Tarija: Arce, valley of the Río Chillaguatas, below Rancho Nogalar on trail between Sidaras and Taroquia, 22°05'S, 64°25'W, fl., 14-16 Oct 1983, J.C. Solomon 11272 (K, MO, US); De Emboruzú a La Mamora, fl., fr., 22 Oct 1980, F.O. Zuloaga et al. 1208 (CORD, SI). PARAGUAY. Without province: s.loc., fl., May 1931, P. Jörgensen 4108 (SI, US). Misiones: Santiago, Estancia La Soledad, fl., 24 Oct 1959, T.M. Pedersen 5219 (L). Guairá: Iturbe, fl., fr., 8 Oct 1952, J.E. Montes 12776 (LIL, LP). Ñeembucú: Estancia Redondo, isla de bosque alto, fl., 25 Jan 2005, M. Vera et al. 230 (BM, FCQ).

Distribution and habitat.

Tradescantia tucumanensis is mainly distributed from Argentina to Bolivia, in the Tucumano-Boliviano Forest formation (Chaco and Andean Yungas domains), but also reaching Paraguay in the dry forests of the Atlantic Forest domain (Fig. 31 ). It can be found growing as a terrestrial or rupicolous herb and seems to be associated with considerably drier habitats than all other species from the T. fluminensis group.

Phenology.

It can be found in bloom and in fruit throughout the year but peaking during the rainy season.

Etymology.

The epithet makes reference to the species distribution, restricted to the Tucumano-Boliviano Forest formation in Argentina and Bolivia.

Conservation status.

Tradescantia tucumanensis possesses a wide EOO (ca. 873,174.442 km2), being widely distributed in Argentina and Paraguay, with few records in Bolivia. It seems to form dense subpopulations and, in accordance with the IUCN recommendations ( IUCN 2001), it should be considered Least Concern (LC).

Comments.

Tradescantia tucumanensis was initially interpreted by me as a new species closely related to T. chrysophylla , due to its stems being sometimes prostrate with ascending apex, involute ptyxis, leaves velutine to hispid, indumentum drying light brown, unequal cincinni bracts (Fig. 30C ), sepals with a mixture of glandular and eglandular hairs (Fig. 30C-E ) and pistil as long as the stamens. Nonetheless, the similarities in gross morphology were quickly observed to be outnumbered by many more relevant differences: its definite base (vs. indefinite in T. chrysophylla ), stems generally erect (vs. always prostrate), leaves generally subpetiolate (vs. always sessile), blades membranous to chartaceous with impressed secondary veins (vs. succulent with inconspicuous secondary veins), sepals keeled (vs. not keeled), hairs along the keel exclusively eglandular (vs. exclusively glandular or with a mixture of glandular and eglandular hairs), seeds with rugose testa (vs. costate) and hilum shorter than ½ the length of the seed (vs. equal ½ the length of the seed). Furthermore, T. tucumanensis is restricted to the Tucumano-Boliviano Forests from Argentina and Bolivia, while T. chrysophylla is endemic to the Atlantic Forest of Brazil. The seed morphology was key in making the connection between T. tucumanensis and T. tenella . Both species are morphologically more closely related due to their: definite base, erect stems (Fig. 30A ), involute ptyxis, membranous to chartaceous leaf-blades (Fig. 30B ), flowers ranging from white to pink (Fig. 30D, E ), seeds with rugose testa and hilum shorter than ½ the length of the seeds. Nonetheless, both species can be differentiated based on the pubescence of the leaf-blades, shape of the floral buds, size of the flowers and pubescence of the sepals (see identification key). Out of these differences, floral bud shape and sepal pubescence have proven to be stable in reliable characters in the taxonomy of T. subg. Austrotradescantia . Furthermore, T. tucumanensis has a preference for drier environments than T. tenella , which is very commonly found growing in damp soil and moss carpets.

Figures

Figure 30. Tradescantia tucumanensis M. Pell A detail of the stem, leaf-sheath and young leaf B adaxial side of the leaf-blade, showing the impressed secondary veins C inflorescence, showing the unequal cincinni bracts, vinaceous pedicels, ellipsoid floral buds and the pubescence of the pedicels and sepals D-E flowers D white petalled flower E light pink petalled flower. A-D by G. A. Parada E by W. M. Ciesla.

Figure 31. Distribution of Tradescantia tucumanensis M. Pell. Orange- Cerrado; Yellow- Chaco and Pantanal; Olive-green- Pampa; Dark green- Atlantic Forest; Purple- Andean Yungas.